1. Field of The Invention
This invention relates generally to couplings for joining fluid transport conduits to each other or to structures with which conduits are designed to communicate, and, more particularly, for joining polymeric hose and tubing to each other and to conduit connection devices. Specifically, the invention relates to improved conduit coupling designs with both quick connect and disconnect features.
2. Description of the Prior Art
Fluid transport conduits are used to convey and pressurize all manner of fluids in such various applications as coolant systems, hydraulic power transmission and actuation systems, pneumatic power transmission and actuation systems, gas, liquid, and solid delivery systems, sensing systems, and the like. For such conduits to be useful, a means must be provided to couple, connect or otherwise join them to each other and to other structures with which they communicate.
One such means is to use a coupling. In such an instance, one portion of the coupling is attached to an open end of a first conduit. The remaining coupling portion is attached to another conduit or structure to which the first conduit is to connect. The two coupling portions are then joined and latched to complete the connection. In order to be completely satisfactory, such couplings must exhibit adequate sealing, load and pressure resistance properties, and resistance to damage by impact.
It is frequently desirable that the joining and latching of the two portions of the coupling can be performed without the aid of tools and by simple and minimal motions on the part of the operator, i.e. the person or machine causing the joining of the coupling. An example of this is where joining and latching is effected by a single thrust of one portion upon the other portion of the coupling. Couplings with this characteristic are sometimes referred to as quick connect couplings.
Likewise, it is frequently desirable that the disjoining and unlatching can be performed with simple and minimal motion from the operator. An example of this is where unlatching is effected by a partial rotation of one portion relative to the other portion thereby allowing the two portions to disjoin. Couplings with this characteristic are sometimes referred to as quick disconnect couplings.
Prior art quick connect coupling designs have utilized many different latching arrangement. These different latching arrangements have required varying levels of motion from the operator, in terms of simplicity and number, during joining. One coupling latch requires the operator to move two or more levers which in turn operate cams which seat in depressions and latch the two portions of the coupling together. Unlatching is the reverse operation. In another latch arrangement, a two-legged pin or staple is placed in slots and grooves of the two portions of the coupling after joining to effect latching. These and other arrangements are as found in U.S. Pat. Nos. 4,894,156, Murken; 4,867,487, Phillis; 4,806,248, Murken; and 4,244,603, Stuemky.
A series of latching arrangements have utilized housings within which sets of fingers are attached extending toward the axis and interior of the conduit that grasp the other portion of the coupling. Some latches of this series make no provision for unlatching. Others of this series allow a portion of the fingers to protrude from the housing. These protrusions can be squeezed to effect unlatching.
In another latch of this series, a collar integral to the coupling can be forced between the fingers and the portion of the coupling that is grasped by the fingers, thereby spreading the fingers to unlatch.
In yet another version, the coupling has a third portion with a set of fingers, arranged as before, and a threaded end. Before the first joining and latching, the threaded end is mated to corresponding threads on the portion of its coupling connected to the first conduit. The remaining portion is attached to the structure with which the conduit is to communicate. Joining and latching is then effected by pushing this combination over the remaining portion. Disjoining and rejoining is thereafter made via the threads. Examples of all of the above can be found in U.S. Pat. Nos. 4,981,586, Bartholomew; 4,948,175, Bartholomew; 4,936,544, Bartholomew; 4,923,228, Laipply; 4,915,421, Dennany Jr.; 4,647,082, Fournier et. al. The above latching arrangement lacks quick disconnect, and quick connect after the first joining and latching operation.
In another style of quick connect coupling latching arrangement, a first portion of the coupling includes a housing with a set of radial holes and associated pins, or slots and associated rings. A collar is slidingly mounted about the housing. The remaining portion of the coupling includes a male member adapted to be inserted in the housing and includes an annular depression that fits inside the housing when the male member is inserted. In one position, the collar compresses the set of pins or rings which in turn impinge upon the male member annular depression, thereby resisting axial movement of one portion relative to the other. In another position, the collar frees the pins or rings from compression, thereby allowing disjoining of the coupling portions. Examples of this type of coupling arrangement can be found in U.S. Pat. Nos. 4,875,715; Dennany Jr. et al. and 3,537,478; Evans et al.
The previously mentioned prior art couplings and associated latching mechanisms all have a variety of drawbacks which include being overly complex to join and latch, devoid of unlatching capability, or overly complex to unlatch. Other deficiencies include having a large outside diameter as compared to the inside diameter of the associated conduits thereby being bulky, requiring excessive free space for latching and unlatching operations, being overly complex and costly to manufacture, being subject to damage or inadvertent disconnect by impact or collection of debris due to exposed portions of the latching mechanism, or being subject to a combination of these disadvantages.
In another style of quick connect coupling, one portion of the coupling includes a housing with a protrusion from one end, adapted to be inserted in the second portion of the coupling for sealing. External hooks are radially disposed around the housing. The second coupling portion includes a bore for receiving the protrusion and an annular ridge disposed thereabout. Joining and latching are apparently effected by simply thrusting the first portion upon the second. The external hooks then slide up, over and around the annular ridge, thereby restraining axial separation of the portions. This style of mechanism has the advantage of requiring the simplest of motions from the operator for joining and latching. Unjoining and unlatching are apparently effected by rotating one portion relative to the other to align the hooks with gaps in the annular ridge, and then pulling the portions apart. One disadvantage of this arrangement is that with the hooks being external to the hose as well as the coupling, they are exposed to damage from impact and debris. Moreover, the hooks are of a shape that allows items of the working environment to lodge in them, and there is apparently no provision to positively limit rotation thereby making the coupling susceptible to inadvertent disconnect. See U.S. Pat. Nos. 4,735,440, Sauer; and 4,708,375, Sauer.
In a variation of this style of coupling the gaps in the annular ridge are absent. This eliminates the inadvertent disconnect problem, but also eliminates the quick disconnect feature. Unlatching is then accomplished by prying or lifting the hooks up over the ridge. See
U.S. Pat. Nos. 4,929,002, Sauer; 4,775,173, Sauer; and 4,775,172, Sauer. U.S. Pat. No. 4,775,172 also discloses extensions attached to the hooks to facilitate their lifting, and an engagement of the hooks with the annular ridge that apparently provides only partial latching. Apparently, if enough force is applied to separate the portions, the latch releases. This style apparently suffers the additional disadvantage of being bulky.
In yet another style of quick connect couplings, a first portion of the coupling includes a housing with a bore adapted to receive a protrusion from a second coupling portion, with hooks around the receiving perimeter of the bore extending from under the open end of the conduit. The second portion includes the protrusion which, sealingly engages the bore, and an annular ridge for receiving and engaging the hooks. The engagement, of the hooks and the ridge, latches the two coupling portions. This style also joins and latches with a single thrust. However, unlatching requires prying hooks away from the ridge. Further, by employing hooks over a ridge, the strength of materials used must be adequate to overcome the inherent weaknesses imposed upon the design where curved members are under compression. This style enjoys the benefit of presenting a small overall diameter for a given hose outside diameter, as compared to other coupling designs, and is sometimes known as a low profile coupling. See U.S. Pat. Nos. 5,044,675, Sauer; 4,978,149, Sauer; 4,969,669, Sauer; 4,969,667, Sauer.
In still another prior quick connect coupling style, a first portion of the coupling includes a cylindrical, circumferentially complete body member adapted to be inserted into and sealingly connected with the open end portion of a hose. The portion of the body member, that extends the deepest into the hose interior, includes an upset bead. A set of prongs extends from this body member upset bead toward the interior axis of the hose. A bore runs through the first portion. The second coupling portion includes a cylindrical projection adapted to be inserted in the bore of the first portion, with an annular ridge for receiving the prongs.
In this coupling style as well as all the other coupling designs discussed above, a sealing mechanism is interposed between the two separated coupling portions prior to their being joined together. Without such sealing mechanism, the couplings would not remain leakproof over time.
Joining and latching is accomplished by a single thrusting of the two portions upon each other, causing the prongs to seat behind and engage the annular ridge. However, since both portions are cylindrical, particularly the second portion, as opposed to frustoconical, there is substantial sliding of the two portions relative to each other before latching occurs. This substantial sliding provides an opportunity for an excessive force requirement to join and latch, due to binding of the two portions, and excessive wear of the sealing means.
This style of coupling does not have quick disconnect capability. Unlatching is effected by first separating the hose from the first portion, then prying the prongs away from the annular ridge. The coupling portions can then be disjoined. However, it does have a low profile, and is not susceptible to damage or inadvertent disconnect because the latching mechanism (i.e., prongs and annular ridge) is internal to the hose.
On the whole, this style of coupling can be used in spaces with minimum surrounding free space and where tools or debris might contact it, but it is apparently not well suited for repeated connect/disconnect operations.
The hose coupling that allows simple thrusting of one portion upon the other to effect joining and latching reduces the cost of assembling fluid transport conduit systems. Where quick connect/disconnect can be effected with minimal force, repeatably and reliably also tends to reduce manufacturing and maintenance costs. Couplings that also feature quick disconnect reduce maintenance costs. Couplings that are not subject to inadvertent disconnect and are resistant to damage from impact or debris reduce the frequency of breakdown. Reducing the number and complexity of the parts that make up a coupling, reduces the cost of manufacture of the coupling.
Consequently a need exists for a coupling that combines the characteristics of: requiring minimal operator motion and force for connection and disconnection; being resistant to inadvertent disconnect; being resistant to damage by impact or debris; requiring minimum free space around the coupling to operate the latch; having a low profile allowing the coupling to fit in limited space applications; and is inexpensive to manufacture because of simplicity, minimal number, and inherent design strength of constituent parts.